Balloon angioplasty is a widely used procedure for expanding constricted body passageways, such as arteries and other blood vessels. In an angioplasty procedure, an uninflated angioplasty balloon attached to a catheter is delivered to a constricted region of a body passageway. Once the balloon is in position at the constricted region, fluid is injected through a lumen of the catheter and into the balloon. The balloon consequently inflates and exerts pressure against the constricted region to expand the passageway. After use, the balloon is collapsed, and the catheter is withdrawn.
Balloons have a number of critical design parameters. One is rated burst pressure, which is the statistically-determined maximum pressure to which a balloon may be inflated without rupturing. In order to expand hard, calcified lesions, it is desirable that the balloon have a rated burst pressure of at least 15 bar. It is also desirable that the balloon have a low wall thickness to minimize the profile of the delivery system. For a given balloon material, however, there is a trade-off between burst pressure and wall thickness, in that the burst pressure generally decreases when the wall thickness is reduced.
Accordingly, there is a need for a means of increasing the strength of a balloon to attain a higher rated burst pressure while maintaining a low delivery profile.